Devices and techniques for hip revision surgery

ABSTRACT

Piezoelectric osteotomy devices and corresponding systems and methods for removing an acetabular cup or shell from a patient&#39;s acetabulum are disclosed. In one embodiment, the piezoelectric osteotomy device includes a piezoelectric element to actuate a cutting tip on an armature. In some such embodiments, the cutting tip may be extended and/or retracted to facilitate cutting of bone around an acetabular cup. The armature may include a fluid output port located proximate the cutting tip to mitigate heat generated by the cutting tip. In one embodiment, the piezoelectric osteotomy device is arranged and configured to provide constant current adjustment.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of pending U.S. application Ser. No.17/080,193, filed Oct. 26, 2020, which is a non-provisional of, andclaims the benefit of the filing date of, U.S. provisional patentapplication No. 62/926,925, filed Oct. 28, 2019, entitled “Devices andTechniques for Hip Revision Surgery” the entirety of each application isincorporated by reference herein in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to devices and techniques forhip revision surgery, and particularly to piezoelectric osteotomydevices and techniques for acetabular shell removal during hip revisionsurgery.

BACKGROUND OF THE DISCLOSURE

Articulating regions of the anatomy can include areas where two bonesections move relative to one another. For example, an acetabulum, orpelvis, can provide a region for articulation with a femoral head.Sometimes, the articulating region, typically referred to as the hipjoint, can become injured or worn, but it can be replaced with variousprostheses. Such prostheses can replace the acetabulum, the femoralhead, and various other portions of the femur, or other combinationsthereof. The replacement of both the acetabulum and the femoral head isgenerally referred to as a total joint replacement.

Acetabular prostheses are one type of prosthesis currently used in jointreplacement. Generally speaking, an acetabular prosthesis includes anacetabular cage coupled via, for example, an adhesive, to an acetabularcup implanted in the acetabulum. Sometimes, a revision surgery isperformed to address issues with a previously implanted acetabular cup.Frequently, the acetabular cup must be removed during such revisionsurgeries. However, damage to bone and/or surrounding vasculature (e.g.,iliac, obturator, pudendal, and/or gluteal vessels) often results fromremoving the acetabular cup.

It is with this in mind that the present disclosure is provided.

SUMMARY OF THE DISCLOSURE

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended asan aid in determining the scope of the claimed subject matter.

The present disclosure provides a medical device including an armaturecomprising a cutting tip and a body coupled to the armature. The bodymay include an actuation mechanism with a piezoelectric element, a userinterface, and an extension mechanism configured to extend the cuttingtip and/or the armature based on operation of the user interface. In oneembodiment, the armature and/or the cutting tip may be configured tomatch a curvature of an acetabular cup. In one embodiment, extension ofthe cutting tip is configured to follow a curvature of an acetabularcup. In one embodiment, the armature may comprise a curvilineararmature.

In one embodiment, the actuation mechanism with the piezoelectricelement may be configured to move the cutting tip at a frequency andamplitude based on operation of the user interface. The frequency of themotion of the cutting tip may be between 22 to 29 kilohertz. In someembodiments, the frequency of the cutting tip may be between 15 and 40kilohertz. The amplitude of the motion of the cutting tip may be between60 and 210 micrometers. In one embodiment, one or more of the frequencyand the amplitude are selectable.

In one embodiment, the piezoelectric element may include one or moreceramic discs. In one embodiment, the actuation mechanism may comprise amotion amplifier to translate motion of the piezoelectric element intomotion of the cutting tip. In one embodiment, the motion of the cuttingtip may have a larger amplitude than the motion of the piezoelectricelement.

In one embodiment, the armature may comprise a fluid output portconfigured to deliver fluid proximate the cutting tip based on operationof the user interface. In one embodiment, the body may include a fluidinput port configured to couple with a fluid source, wherein the fluidinput port is in fluid communication with the fluid output port, atleast in part, via a fluid channel in the armature.

In one embodiment, the body may comprise a drive signal input configuredto couple with a signal generator. In one embodiment, the actuationmechanism is configured to apply an electromagnetic field to thepiezoelectric element based on a signal received via the drive signalinput to cause motion in the cutting tip. In one embodiment, theextension mechanism may include a worm gear.

The present disclosure provides a method comprising operating, via auser interface, an actuation mechanism with a piezoelectric elementcomprised in a body to cause motion in a cutting tip included in anarmature coupled to the body. In one embodiment, the method may includeextending the armature and/or cutting tip. In one embodiment, the methodmay include causing fluid to exit a fluid output port proximate thecutting tip based on operation of the user interface. In one embodiment,the method may include operating the user interface to extend thecutting tip and/or the armature. In one embodiment, extension of thecutting tip may be configured to follow the curvature of the acetabularcup. In one embodiment, the method may include controlling one or moreof amplitude and frequency of motion in the cutting tip based onoperation of the user interface.

Embodiments of the present disclosure provide numerous advantages. Forexample, in accordance with the present disclosure, devices, systems,and methods for reducing bone and/or vasculature damage during removalof an acetabular implant is provided.

Further features and advantages of at least some of the embodiments ofthe present disclosure, as well as the structure and operation ofvarious embodiments of the present disclosure, are described in detailbelow with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

By way of example, a specific embodiment of the disclosed device willnow be described, with reference to the accompanying drawings, in which:

FIG. 1 includes a block diagram of an exemplary medical device,according to one or more embodiments described herein;

FIGS. 2A-2C illustrate various features of an exemplary actuationmechanism for a medical device, according to one or more embodimentsdescribed herein;

FIG. 3 illustrates an exemplary medical device, according to one or moreembodiments described herein;

FIG. 4 illustrates various features of an exemplary medical device inconjunction with an acetabular cup, according to one or more embodimentsdescribed herein; and

FIGS. 5A and 5B illustrate various features of an exemplary medicaldevice, according to one or more embodiments described herein.

The drawings are not necessarily to scale. The drawings are merelyrepresentations, not intended to portray specific parameters of thedisclosure. The drawings are intended to depict example embodiments ofthe disclosure, and therefore are not be considered as limiting inscope. In the drawings, like numbering represents like elements.

Furthermore, certain elements in some of the figures may be omitted, orillustrated not-to-scale, for illustrative clarity. The cross-sectionalviews may be in the form of “slices”, or “near-sighted” cross-sectionalviews, omitting certain background lines otherwise visible in a “true”cross-sectional view, for illustrative clarity. Furthermore, forclarity, some reference numbers may be omitted in certain drawings.

DETAILED DESCRIPTION

Various features or the like of a piezoelectric osteotomy devicearranged and configured to remove an acetabular cup or shell from apatient's acetabulum will now be described more fully hereinafter withreference to the accompanying drawings, in which one or more features ofthe piezoelectric osteotomy device will be shown and described. Itshould be appreciated that the various features may be usedindependently of, or in combination, with each other. It will beappreciated that a piezoelectric osteotomy device and correspondingsystems and methods as disclosed herein may be embodied in manydifferent forms and should not be construed as being limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will convey certain features of the piezoelectricosteotomy device and accompanying system and method to those skilled inthe art.

Embodiments of improved devices and techniques for hip revision surgerywill now be described more fully hereinafter with reference to theaccompanying drawings. Various embodiments are generally directed topiezoelectric osteotomy devices, systems, and methods for removing anacetabular cup or shell (used interchangeably herein without the intentto limit) from a patient's acetabulum while minimizing disruption to theexisting, potentially compromised host bone. In one embodiment, thepiezoelectric osteotomy device includes a piezoelectric element arrangedand configured to actuate a cutting tip on an armature. In some suchembodiments, the armature and/or the cutting tip may be extended and/orretracted to facilitate cutting of bone around the acetabular cup. Thearmature may include a fluid output port located proximate the cuttingtip to mitigate heat generated by the cutting tip. These and otherembodiments are described and claimed.

Some challenges facing hip revision surgery include removing theacetabular cup without causing excess damage to the surrounding boneand/or vasculature. These challenges may result from the growth of bonearound an implanted acetabular cup, which includes cancellous bone thatis more fragile than cortical bone in the rest of the pelvis.Additionally, the acetabulum is heavy in vasculature, which can lead toincreased blood loss and higher vessel damage. Adding furthercomplexity, many techniques for acetabular cup removal incorporatetorque/mechanically operated instruments, leading to undue bone damageand vasculature damage. For example, a surgeon may attach an instrumentto the acetabular cup, and pull it out, resulting in excessive removalof bone attached to the acetabular cup. Further, torque/mechanicallyoperated instruments are imprecise and require unnecessary physicalexertion to operate. These known techniques present great risk to thepelvic area of a patient because of the fragile bone and heavilyvasculature around the acetabular cup. These and other factors mayresult in devices, systems, and methods for hip revision surgery thatare difficult to use, unsafe, inaccurate, inefficient, and unreliable,resulting in limited applicability and/or uncertain outcomes. Suchlimitations can drastically reduce the dependability, ergonomics,effectiveness, and safety of hip revision surgeries, contributing toreduced usability, adverse outcomes, excess fatigue, and lost revenues.

Various embodiments described herein include piezoelectric osteotomydevices, components, and techniques that enable high precisionacetabular shell removal during hip revision surgery that limits damageto bone and/or vasculature. Further, limiting damage to vasculature canreduce bleeding and improve visibility. In many embodiments, apiezoelectric element may operate a cutting tip at a selectablefrequency to limit damage. For example, the cutting tip may be operatedat a frequency to cut bone, which may be unique from a frequency to cutvasculature and soft tissue. In many embodiments, the cutting tip mayextend out of an armature such as, for example, to allow for curvilinearosteotomy that matches the curvature of the acetabular cup.

In several embodiments, devices may include plumbing to enable fluid tobe delivered proximate the cutting tip, such as for cooling and/orirrigation. For instance, cooling fluid may be delivered proximate thecutting tip to prevent thermal necrosis. In many embodiments, flow ofthe fluid may be controlled with the same interface as the piezoelectricelement, providing a 2-in-1 system that is intuitive, ergonomic, andconvenient. In many such embodiments, the flow of fluid, frequency ofthe cutting tip, extension of the cutting tip, and/or extension of thearmature may be controlled with one hand or finger. In variousembodiments, one or more of the components may be designed to simplifymanufacturability, configurability, and/or adaptability. For example,cutting tips may be replaceable/exchangeable such as to allow differentcutting tips to be utilized at different frequencies. In someembodiments, one or more components may be designed to work withexisting devices, such as a signal generator or fluid source in anoperating room. In these and other ways, components/techniques describedhere may improve operator experience, decrease learning curves, increasereliability, limit bone/vasculature damage, improve outcomes, and/ordecrease recovery time for hip revision surgeries via realization ofmore efficient and valuable devices, systems, and methods for hiprevision surgery.

FIG. 1 illustrates a block diagram of an exemplary medical device 102 inenvironment 100, according to one or more embodiments described herein.In some embodiments, one or more components of environment 100 may bethe same or similar to one or more other components described herein.Environment 100 may include medical device 102 with body 104 andarmature 122. The body 104 may include one or more of an actuationmechanism 106, a drive signal input 114, a fluid input port 116, a userinterface 118, and an extension mechanism 120. The actuation mechanism106 may also include a signal conditioner 108, a piezoelectric element110, and a motion amplifier 112. The armature 122 may include a fluidchannel 124, a fluid output port 126, and a cutting tip 128. In severalembodiments described herein, one or more components of the medicaldevice 102 may interoperate to enable safe and efficient acetabularshell removal, such as during hip revision surgery. Embodiments are notlimited in this context.

In various embodiments, the actuation mechanism 106 may be utilized togenerate movement in the cutting tip 128 of the armature 122. Forexample, the signal conditioner 108 may apply an electric/magnetic fieldto the piezoelectric element 110 based on a drive signal received viathe drive signal input 114 to generate movement in the cutting tip 128of the armature 122. In various embodiments, the drive signal may begenerated and provided to the drive signal input 114 by an electricsignal generator. For example, an electric generator located in amedical facility, such as an operating room, may be used to generate thedrive signal. In many embodiments, the drive signal may be analternating current signal. In other embodiments, the drive signal maybe a direct current signal. The signal conditioner 108 may generate anelectromagnetic field to induce motion in the piezoelectric element 110based on the drive signal. In some embodiments, the signal conditioner108 may alter and/or control one or more characteristics of the drivesignal. For instance, the signal conditioner 108 may amplify one or morefeatures of the drive signal. In another, or additional, instance, thesignal conditioner 108 may convert the drive signal from direct currentto alternating current. In several embodiments, the actuation mechanism106 may be enclosed by the body 104. In various embodiments, theactuation mechanism 106, or one or more components thereof, may bedirectly mounted to the body 104.

In many embodiments, signal conditioner 108 may induce forces and/ormovement in the piezoelectric element 110 via exposure to anelectromagnetic field generated from, or included in, the drive signal.In many such embodiments, the forces and/or movement in thepiezoelectric element 110 may include one or more of linear,compression, strain, stress. In various embodiments, the piezoelectricelement 110 may include a piezoelectric crystal that vibrates uponapplication of an electromagnetic field. In some embodiments, thepiezoelectric element 110 may include one or more piezoelectric ceramicdiscs.

In one or more embodiments, the motion amplifier 112 may couple thepiezoelectric element 110 to the armature 122. In many embodiments, themotion amplifier 112 may translate force and/or motion induced in thepiezoelectric element 110 into motion of the cutting tip 128. Forexample, motion amplifier 112 may cause the motion of the cutting tip128 to have a larger amplitude than the motion of the piezoelectricelement 110. In some embodiments, the armature 122 may operate as, orinclude, a waveguide to facilitate the transfer of motion to the cuttingtip 128. In various embodiments, one or more portions of the cutting tip128 may operate as, or include, a waveguide to facilitate the transferof motion to the distal end of the cutting tip 128. In some embodiments,the expected ultrasonic movements may be small and generally lateral.These movements may be amplified by a horn section comprised in themotion amplifier 112. In some embodiments, the ultrasonic movements maybe amplified by the waveguide (e.g., armature 122 and/or cutting tip128). For example, the waveguide may taper to the distal end of thecutting tip.

In several embodiments, motion of the cutting tip 128 may include one ormore of a linear, reciprocating, angular, and/or hammering motions. Inmany embodiments, the actuation mechanism 106 may cause the cutting tip128 to move at a specific frequency and/or amplitude or range offrequencies/amplitudes. For instance, the cutting tip 128 may be movedat a frequency and amplitude that will cut bone and not vasculature orsoft tissue (e.g., frequency range of 22 to 29 kilohertz and amplituderange of 60 to 210 micrometers). In some embodiments, the frequencyand/or amplitude of the cutting tip 128 may be controllable/selectable,such as via user interface 118. For instance, the frequency may beadjusted to above 50 kilohertz for cutting neurovascular tissue and/orother soft tissues.

As previously mentioned, the armature 122 may include a fluid channel124 and a fluid output port 126. In many embodiments, the fluid outputport 126 may be located proximate the cutting tip 128 and the fluidchannel 124 may place the fluid output port 126 in fluid communicationwith the body 104 of the medical device 102. In various embodiments, thefluid input port 116 may enable a fluid from a fluid source to besupplied, or delivered, to the fluid output port 126 of the armature 122via the fluid channel 124. In several embodiments, the fluid source mayinclude a fluid pouch with a tube that connects to the fluid input port116. In many embodiments, the body 104 may include plumbing to place thefluid input port 116 in fluid communication with the fluid channel 124of the armature 122.

In various embodiments, the armature 122 and/or cutting tip 128 may bereplaceable/selectable. In various such embodiments, a variety ofarmatures and/or cutting tips may be available to customize theconfiguration of the medical device 102 for specific needs. For example,an armature and/or cutting tip may be selected to match the degree ofcurvature for a specific acetabular cup. In another example, the cuttingtip 128 may be selected based on the frequency and/or amplitudeimplemented by the actuation mechanism 106. In yet another example, thecutting tip 128 may be selected based on the type, or lack thereof, offluid provided via the fluid output port 126. In some embodiments, thearmature and/or cutting tip may be curvilinear. In one or moreembodiments, the medical device (e.g., piezoelectric osteotomy device)102 may be provided in a kit including a plurality of differently sizedand/or configured armatures and/or cutting tips.

In some embodiments, the user interface 118 may be used to control fluidflow from the fluid input port 116 to the fluid output port 126. Forexample, the user interface 118 may be used to operate a pump, a valve,etc. to control fluid flow from the fluid input port 116 to the fluidoutput port 126. In one or more embodiments, fluid flow out of the fluidoutput port 126 may be utilized to remove, or at least minimize, heatfrom the cutting tip 128 or surrounding anatomy. For instance, the fluidmay include refrigerated saline. In many embodiments, fluid flow out ofthe fluid output port 126 may be used to prevent thermal necrosis. Invarious embodiments, the temperature of the fluid may be selectable. Forexample, the fluid may be used to cyclically cool and heat an implant(e.g., acetabular cup) and/or the surrounding anatomy. In such examples,cyclically cooling and heating the implant and/or surrounding anatomymay assist in removal of the implant. In some embodiments, fluid flowand motion of the cutting tip 128 may be controlled by a common controlin the user interface 118. For instance, a single actuating mechanismsuch as, for example, a button, may cause fluid to flow and actuation ofthe cutting tip 128.

In many embodiments, the extension mechanism 120 may enable extensionand retraction of the armature 122 and/or the cutting tip 128. In someembodiments, the extension mechanism 120 may enable curvilinearosteotomy with the cutting tip 128 of the armature 122 that matches thecurvature of an acetabular cup. In one or more embodiments,extension/retraction of the cutting tip 128 may be controlled via theuser interface 118. In some embodiments, the extension mechanism 120 mayutilize a worm gear to advance/retract the armature 122 and/or cuttingtip 128, although other mechanisms for advancing and retracting thearmature and/or cutting tip are envisioned. For example, a wheel may berolled in a first direction to extend the cutting tip 128 and a seconddirection to retract the cutting tip 128 (see e.g., FIG. 3 ). In manyembodiments, extension of the cutting tip 128 may enable a manual methodto advance a curved blade along the back side of an ingrown acetabularshell.

In one or more embodiments, a shape memory material, such as ashape-memory metal, may be used to instantiate curvature in the armature122 and/or cutting tip 128. In some embodiments, portions of the cuttingtip 128 retracted into the armature 122 may be held in a straightenedstate by the armature, while portions of the cutting tip 128 extendedout of the armature 122 may curve to match the curvature of anacetabular cup. In other words, the armature 128 may limit the amount ofbend in portions of the cutting tip 128 until those portions areextended out of the armature. In various embodiments, the armature 122and/or cutting tip 128 may be constructed from surgical grade stainlesssteel, titanium, and/or alloys thereof, although it is envisioned thatthe armature and/or cutting tip may be manufactured from any suitablematerial now known or hereafter developed. In some embodiments, thearmature 122 and/or cutting tip 128 may be coated. For example, thecutting tip 128 may include a titanium nitride coated steel blade tip.

In several embodiments, the user interface 118 may include one or moreactuating mechanisms such as, for examples, buttons, switches, controls,wheel, knobs, interface members, etc. or a combination thereof. Forexample, the user interface 118 may include one or more of a wheel tocontrol extension/retraction of the cutting tip 128, a first knob tocontrol the frequency of the cutting tip 128, a second knob to controlthe amplitude of the cutting tip 128, and a button to control start andstop movement of the cutting tip 128 as well as fluid flow out of thefluid output port 126. In some embodiments, the user interface 118 mayprovide feedback, such as the current frequency and/or amplitude settingof the cutting tip 128. In several embodiments, the body 104 may includea handle that allows for ergonomic hand placement for a user. Further,the handle, in conjunction with the user interface 118, may beconfigured to enable single-handed, or single-fingered, operation of themedical device 102. For example, single-handed blade extension maysimplify maneuvering the cutting tip 128 around a span of an acetabularcup.

FIGS. 2A-2C illustrate an example of an embodiment of an actuationmechanism 206 for a medical device 202 in environments 200A, 200B, 200C,according to one or more embodiments described herein. In someembodiments, one or more components of environments 200A, 200B, 200C maybe the same or similar to one or more other components described herein.Environments 200A, 200B, 200C may include signal generator 230 inconjunction with medical device 202. The medical device 202 may includeactuation mechanism 206 with drive signal input 214, signal conditioner208, and piezoelectric element 210. In many embodiments, thepiezoelectric element 210 may be polarized with a positive pole locatedtoward the top and a negative pole located toward the bottom. In one ormore embodiments described herein, signal conditioner 208 may applysignals of different polarizations to cause deformation in piezoelectricelement 210, such as via the reverse piezoelectric effect. In one ormore such embodiments, these deformations may be used to cause a cuttingmotion in the cutting tip. Embodiments are not limited in this context.

Accordingly, in environment 200A, piezoelectric element 210 may have afirst height 205A and a first width 215A. Further, actuation mechanism206 may be in a standby state with no signal being applied topiezoelectric element 210. In environment 200B, piezoelectric element210 may have a second height 205B and a second width 215B. Further,actuation mechanism 206 may be in a state with a positive-polarizedsignal being applied to piezoelectric element 210 via signal conditioner208. In environment 200C, piezoelectric element 210 may have a thirdheight 205C and a third width 215C. Further, actuation mechanism 206 maybe in a state with a negative-polarized signal being applied topiezoelectric element 210 via signal conditioner 208. Accordingly, theheight 205A may be less than the height 205B and greater than the height205C; and the width 215A may be greater than the width 215B and lessthan the width 215C.

In one or more embodiments, the signal conditioner 208 or the signalgenerator 230 may comprise, or function as, a controlled voltage/currentsource. In various embodiments, the controlled voltage/current sourcemay monitor current and/or voltage flowing to the piezoelectric element210. In various such embodiments, the controlled voltage/current sourcemay adjust the current and/or voltage flowing to the piezoelectricelement 210 based on monitoring of the current and/or voltage flowing tothe piezoelectric element 210. In several embodiments, the controlledvoltage/current source may adjust the current/voltage flow to maintain aconstant resonance in the cutting tip. In some embodiments, whenresonating, the current and voltage waveforms may be out of phase (e.g.,orthogonal) to each other. However, when not resonating, the current andvoltage waveforms may be in phase with each other. Accordingly, invarious embodiments, the controlled voltage/current source may maintainthe current and voltage waveforms orthogonal with respect to each other.

In many embodiments, the controlled voltage/current source may adjustthe current/voltage flowing to the piezoelectric element 210 to keep thecutting tip resonating in a safe and effective manner. For example, adrop in current may indicate the cutting tip is being dampened, such aswhen it is cutting bone. In such examples, the voltage may be increasedto keep the cutting tip resonating. In another example, an increase iscurrent may indicate the cutting tip is over resonating, such as when itis actuating without resistance (e.g., in the air). In such otherexamples, the current may be decreased to prevent damage to theactuation mechanism, the armature, and/or the cutting tip, such as dueto over resonating.

In several embodiments, the piezoelectric element may include one ormore of crystals, ceramics, berlinite, cane sugar, quartz, rochellesalt, topaz, tourmaline, bone, barium titanate, lead zirconate titanate,bismuth, gallium phosphate, and the like. In many embodiments, materialsof the piezoelectric element 110 may be chosen to improve heat toleranceof the medical device 102. In some embodiments, high voltages may inducechanges in the width of the piezoelectric element 210. In variousembodiments, when the piezoelectric element 210 is subjected to anelectrical and/or magnetic field, it may expand/contract in a directproportion to the electrical and/or magnetic field. In many embodiments,application of electric/magnetic fields to the piezoelectric element 210may facilitate a linear micro-motion of the cutting tip as opposed to arotary macro-motion.

In various embodiments, one or more components of the medical device 102may be constructed from materials selected based on their ability tohandle ultrasonic stresses. In many embodiments, one or more portions ofthe waveguide, armature, and/or cutting tip may be constructed frommetal, such as stainless steel or a titanium alloy, although othersuitable materials now known or hereafter developed may be used.Typically, ultrasonic stresses may peak approximately an eighth or asixteenth of a wavelength from the tip. Accordingly, some embodimentsmay include reinforcing approximately an eighth or a sixteenth of awavelength from the tip.

For example, in various embodiments, steel and/or titanium may beselected. In connection with embodiments where titanium is used, with aresonant frequency of 23 kHz, in titanium (in which the speed of soundis 6070 m/s) an eighth of a wavelength from the tip would be, in oneembodiment, approximately 3.42 cm and a sixteenth of a wavelength fromthe tip would be approximately 1.71 cm. In connection with embodimentswhere steel is used, with a resonant frequency of 23 kHz, in steel (inwhich the speed of sound is 5790 m/s) an eighth of a wavelength from thetip would be, in one embodiment, approximately 3.15 cm and a sixteenthof a wavelength from the tip would be approximately 1.57 cm.

In some embodiments, titanium may be used to save weight. For instance,titanium can be 45% lighter than steel. Further, titanium may be moredurable and resistant to plastic deformation. Steel may be stronger, butfatigue easier than titanium. Titanium may be used to provide more heattolerance than steel. Titanium may provide improved corrosionresistance. Further, titanium is nonmagnetic while steel is magnetic. Insome embodiments, the nonmagnetic properties of titanium may be used toprevent interference with, or by, the piezoelectric element 110. In someembodiments, the magnetic properties of steel may be used to promote orutilize magnetic fields. Oftentimes, steel may be used where strength isneeded in hard material and titanium may be used where a lightweight andstrong material is needed. In one or more embodiments, steel may be usedto reduce cost and enable disposable components. In some embodiments,the waveguide (e.g., armature and/or cutting tip) may bereplaceable/disposable.

FIG. 3 illustrates an exemplary medical device 302 (e.g., apiezoelectric osteotomy device) in environment 300, according to one ormore embodiments described herein. In some embodiments, one or morecomponents of environment 300 may be the same or similar to one or moreother components described herein. For example, medical device 102 maybe the same or similar to medical device 302. Environment 300 includesmedical device 302 with a proximal end 325 and a distal end 335. Asshown, the medical device 302 may include a body 304 and an armature322. The body 304 may include one or more of a drive signal input 314, afluid input port 316, a user interface 318, an extension mechanism 320,thermal insulation 334, insulating stopper 332, and an actuationmechanism with a signal conditioner 308, a piezoelectric element 310,and a motion amplifier 312. The insulating stopper 332 may electricallyisolate the actuation mechanism from armature 322 and/or cutting tip328. For example, the insulating stopper 332 may insulate the cuttingtip 328 from the electrical signal that drives the piezoelectricelements (e.g., the drive signal or signal based thereon) fromconducting to the cutting tip 328 thus preventing the electrical signalfrom making direct contact with the patient via the cutting tip 328. Thearmature 322 may include a fluid channel 324, a fluid output port 326,and a cutting tip 328. In several embodiments described herein, one ormore components of the medical device 302 may interoperate to enablesafe and efficient acetabular shell removal, such as during hip revisionsurgery. For instance, the cutting tip 328 may extend out of thearmature 322 with a curvature that matches the curvature of anacetabular cup (see e.g., FIG. 4 ). Embodiments are not limited in thiscontext.

In the illustrated embodiment, user interface 318 may include amechanism such as, for example, a wheel that can be rotated in a firstdirection to extend the cutting tip 328 and can be rotated in a seconddirection to retract the cutting tip 328. In many embodiments, themechanism of the user interface 318 may operate the extension mechanism320 to cause the cutting tip 328 to extend/retract. In some embodiments,the wheel may be depressed to cause motion in the cutting tip 328 and orfluid flow through the fluid output port 326. In various embodiments,the thermal insulation 334 may prevent, or limit, heat generated in thebody 304 from heating the surface of the body 304 and/or the userinterface 318. For example, the piezoelectric element 110 may generateheat that the user interface 118 is insulated from by thermal insulation334. In some embodiments, the thermal insulation 334 may prevent, orlimit, heat generated by the medical device 302 from heating coolingfluid provided from fluid input port 316 and delivered to fluid outputport 326 via fluid channel 324.

In one or more embodiments, the medical device 102 may include a heatsink or heat exchanger to remove heat from the actuation mechanism 106.For instance, fluid may be circulated to remove heat from thepiezoelectric element 110. Exposing the piezoelectric element 110 toexcessive heat may cause depolarization, reduced effectiveness, and/orreduced component life. In many embodiments, materials in thepiezoelectric element 110 may be chosen to improve heat tolerance.

FIG. 4 illustrates various features of an exemplary medical device 402in conjunction with an acetabular cup 438 in environment 400, accordingto one or more embodiments described herein. In some embodiments, one ormore components of environment 400 may be the same or similar to one ormore other components described herein. For example, medical device 402may be the same or similar to medical device 302. Environment 400illustrates a distal portion of medical device 402 with extensions442-1, 442-2 of cutting tip 428 out of armature 422. Extension 442-1 maydemonstrate positioning of the cutting tip 428 in a retracted state suchthat distal end 435-1 is the distal end of cutting tip 428. Extension422-2 may demonstrate positioning of the cutting tip 428 in an extendedstate such that distal end 435-2 is the distal end of cutting tip 428.In one or more embodiments described herein, curvature of the extendedportion of cutting tip 428 may match the curvature of the acetabular cup438. Embodiments are not limited in this context.

In many embodiments, the medical device 402 may be operated tocontinuously transition the cutting tip 428 between extension 422-1 andextension 422-2. In many embodiments, extension 422-2 may position thedistal end 435-2 at or beyond the apex of the acetabular cup 438. Inmany such embodiments, positioning the distal end 435-2 at or beyond theapex of the acetabular cup 438 enables access to all bone around theacetabular cup 438 with the cutting tip 428 by rotating the medicaldevice 402 about the acetabular cup 438. In some embodiments, cuttingtip 428 may be retracted further than extension 442-1 and/or extendedfurther than extension 442-2. For example, the end of cutting tip 428may be retracted all the way into armature 422. In such examples,retracting cutting tip 428 into armature 422 may prevent or limitunintended contact with or damage to the cutting tip 428. In manyembodiments, a user interface of the medical device 402 may be operatedto transition the cutting tip 428 from the retracted state to theextended state in a continuous manner to advance the cutting tip 428along the back side of an ingrown acetabular shell.

FIGS. 5A and 5B illustrate various features of an exemplary medicaldevice 502 in environments 500A, 500B, according to one or moreembodiments described herein. In some embodiments, one or morecomponents of environments 500A, 500B may be the same or similar to oneor more other components described herein. For example, medical device502 may be the same or similar to medical device 402. Environments 500A,500B include medical device 502 with a proximal end 525 and a distal end535. The medical device 502 may include a body 504 with handle 540, auser interface 518, and an armature 522 with a fluid output port 526 anda cutting tip 528. In various embodiments, medical device 502 may enablelinear extension of the armature 522. Embodiments are not limited inthis context.

In one or more embodiments, medical device 502 may employ analternative, or additional, type of extension than employed by medicaldevice 402. In many embodiments, the type of extension employed bymedical device 502 may be used to adjust for the anatomy of a patient.For instance, extension 542-2 may be utilized on patients with largeranatomies. In environment 500A, the armature 522 is illustrated in aretracted state with extension 522-1. In environment 500B, the armature522 is illustrated in an extended state with extension 542-2.Accordingly, extension 542-1 may be less than extension 542-2. In one ormore embodiments described herein, user interface 518 may be operated totransition the armature 522 from the retracted state to the extendedstate in a continuous manner.

In one or more such embodiments, user interface 518 may be operated witha single hand to transition the armature from the retracted state to theextended state. In some embodiments, the handle 540 may include one ormore ergonomic features (e.g., grip, padding, textures, antimicrobialsurfaces, finger grooves, and the like) to improve user experience. Forinstance, handle 540 may include features for enabling single-handed useor simplifying cleaning. In some instances, handle 540 may includefeatures for enabling single-finger actuation of user interface 518. Inone or more embodiments, medical device 402 may include one or morecomponents/features that are the same or similar to those of medicaldevice 502, such as body 504, user interface 518, fluid output port 526,and handle 540.

While the present disclosure refers to certain embodiments, numerousmodifications, alterations, and changes to the described embodiments arepossible without departing from the sphere and scope of the presentdisclosure, as defined in the appended claim(s). Accordingly, it isintended that the present disclosure not be limited to the describedembodiments, but that it has the full scope defined by the language ofthe following claims, and equivalents thereof. The discussion of anyembodiment is meant only to be explanatory and is not intended tosuggest that the scope of the disclosure, including the claims, islimited to these embodiments. In other words, while illustrativeembodiments of the disclosure have been described in detail herein, itis to be understood that the inventive concepts may be otherwisevariously embodied and employed, and that the appended claims areintended to be construed to include such variations, except as limitedby the prior art.

Directional terms such as top, bottom, superior, inferior, medial,lateral, anterior, posterior, proximal, distal, upper, lower, upward,downward, left, right, longitudinal, front, back, above, below,vertical, horizontal, radial, axial, clockwise, and counterclockwise)and the like may have been used herein. Such directional references areonly used for identification purposes to aid the reader's understandingof the present disclosure. For example, the term “distal” may refer tothe end farthest away from the medical professional/operator whenintroducing a device into a patient, while the term “proximal” may referto the end closest to the medical professional when introducing a deviceinto a patient. Such directional references do not necessarily createlimitations, particularly as to the position, orientation, or use ofthis disclosure. As such, directional references should not be limitedto specific coordinate orientations, distances, or sizes, but are usedto describe relative positions referencing particular embodiments. Suchterms are not generally limiting to the scope of the claims made herein.Any embodiment or feature of any section, portion, or any othercomponent shown or particularly described in relation to variousembodiments of similar sections, portions, or components herein may beinterchangeably applied to any other similar embodiment or feature shownor described herein.

While the present disclosure refers to certain embodiments, numerousmodifications, alterations, and changes to the described embodiments arepossible without departing from the sphere and scope of the presentdisclosure, as defined in the appended claim(s). Accordingly, it isintended that the present disclosure not be limited to the describedembodiments. Rather these embodiments should be considered asillustrative and not restrictive in character. All changes andmodifications that come within the spirit of the invention are to beconsidered within the scope of the disclosure. The present disclosureshould be given the full scope defined by the language of the followingclaims, and equivalents thereof. Unless otherwise defined, all technicalterms used herein have the same meaning as commonly understood by one ofordinary skill in the art to which the disclosure belongs.

The foregoing description has broad application. The discussion of anyembodiment is meant only to be explanatory and is not intended tosuggest that the scope of the disclosure, including the claims, islimited to these embodiments. In other words, while illustrativeembodiments of the disclosure have been described in detail herein, itis to be understood that the inventive concepts may be otherwisevariously embodied and employed, and that the appended claims areintended to be construed to include such variations, except as limitedby the prior art.

It should be understood that, as described herein, an “embodiment” (suchas illustrated in the accompanying Figures) may refer to an illustrativerepresentation of an environment or article or component in which adisclosed concept or feature may be provided or embodied, or to therepresentation of a manner in which just the concept or feature may beprovided or embodied. However, such illustrated embodiments are to beunderstood as examples (unless otherwise stated), and other manners ofembodying the described concepts or features, such as may be understoodby one of ordinary skill in the art upon learning the concepts orfeatures from the present disclosure, are within the scope of thedisclosure. Furthermore, references to “one embodiment” of the presentdisclosure are not intended to be interpreted as excluding the existenceof additional embodiments that also incorporate the recited features.

In addition, it will be appreciated that while the Figures may show oneor more embodiments of concepts or features together in a singleembodiment of an environment, article, or component incorporating suchconcepts or features, such concepts or features are to be understood(unless otherwise specified) as independent of and separate from oneanother and are shown together for the sake of convenience and withoutintent to limit to being present or used together. For instance,features illustrated or described as part of one embodiment can be usedseparately, or with another embodiment to yield a still furtherembodiment. Thus, it is intended that the present subject matter coverssuch modifications and variations as come within the scope of theappended claims and their equivalents.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralelements or steps, unless such exclusion is explicitly recited. It willbe further understood that the terms “comprises” and/or “comprising,” or“includes” and/or “including” when used herein, specify the presence ofstated features, regions, steps, elements and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components and/or groupsthereof.

The phrases “at least one”, “one or more”, and “and/or”, as used herein,are open-ended expressions that are both conjunctive and disjunctive inoperation. The terms “a” (or “an”), “one or more” and “at least one” canbe used interchangeably herein.

Connection references (e.g., engaged, attached, coupled, connected, andjoined) are to be construed broadly and may include intermediate membersbetween a collection of elements and relative to movement betweenelements unless otherwise indicated. As such, connection references donot necessarily infer that two elements are directly connected and infixed relation to each other. Identification references (e.g., primary,secondary, first, second, third, fourth, etc.) are not intended toconnote importance or priority, but are used to distinguish one featurefrom another. The drawings are for purposes of illustration only and thedimensions, positions, order and relative to sizes reflected in thedrawings attached hereto may vary.

The foregoing discussion has been presented for purposes of illustrationand description and is not intended to limit the disclosure to the formor forms disclosed herein. For example, various features of thedisclosure are grouped together in one or more embodiments orconfigurations for the purpose of streamlining the disclosure. However,it should be understood that various features of the certain embodimentsor configurations of the disclosure may be combined in alternateembodiments or configurations. Moreover, the following claims are herebyincorporated into this Detailed Description by this reference, with eachclaim standing on its own as a separate embodiment of the presentdisclosure.

1. A cutting instrument, comprising a body including: a cutting tip; anactuation mechanism operatively associated with a piezoelectric element;a user interface; and an extension mechanism configured to extend thecutting tip relative to the body based on operation of the userinterface.
 2. The cutting instrument of claim 1, wherein the cutting tipis configured to match a curvature of an acetabular cup.
 3. The cuttinginstrument of claim 1, wherein extension of the cutting tip isconfigured to follow a curvature of an acetabular cup.
 4. The cuttinginstrument of claim 1, wherein the actuation mechanism and thepiezoelectric element are configured to move the cutting tip at afrequency and amplitude based on operation of the user interface.
 5. Thecutting instrument of claim 4, wherein the frequency is between 22 to 29kilohertz.
 6. The cutting instrument of claim 4, wherein the amplitudeis between 60 and 210 micrometers.
 7. The cutting instrument of claim 4,wherein one or more of the frequency and the amplitude are selectable.8. The cutting instrument of claim 1, wherein the piezoelectric elementcomprises one or more ceramic discs.
 9. The cutting instrument of claim1, wherein the actuation mechanism comprises a motion amplifier totranslate motion of the piezoelectric element into motion of the cuttingtip.
 10. The cutting instrument of claim 9, wherein the motion of thecutting tip has a larger amplitude than the motion of the piezoelectricelement.
 11. The cutting instrument of claim 1, wherein the body furtherincludes a fluid output port configured to deliver fluid proximate thecutting tip based on operation of the user interface.
 12. The cuttinginstrument of claim 11, wherein the body further includes a fluid inputport configured to couple with a fluid source, wherein the fluid inputport is in fluid communication with the fluid output port, at least inpart, via a fluid channel.
 13. The cutting instrument of claim 1,wherein the body further includes a drive signal input, the drive signalinput configured to couple with a signal generator.
 14. The cuttinginstrument of claim 13, wherein the actuation mechanism is configured toapply an electromagnetic field to the piezoelectric element based on asignal received via the drive signal input to cause motion in thecutting tip.
 15. The cutting instrument of claim 1, wherein theextension mechanism comprises a worm gear.
 16. A cutting instrumentarranged and configured to cut a previously implanted acetabular cupfrom a patient's bone, the cutting instrument comprising a bodyincluding: a curvilinear cutting tip configured to match a curvature ofthe acetabular cup; an actuation mechanism operatively associated with apiezoelectric element; a user interface; and an extension mechanismconfigured to extend the cutting tip relative to the body at a frequencyand an amplitude based on operation of the user interface, the frequencybeing between 22 to 29 kilohertz.
 17. The cutting instrument of claim16, wherein extension of the cutting tip is configured to follow thecurvature of the acetabular cup.
 18. The cutting instrument of claim 16,wherein the amplitude is between 60 and 210 micrometers.
 19. The cuttinginstrument of claim 16, wherein one or more of the frequency and theamplitude are selectable.
 20. The cutting instrument of claim 16,wherein the piezoelectric element comprises one or more ceramic discs.21. The cutting instrument of claim 16, wherein the actuation mechanismcomprises a motion amplifier to translate motion of the piezoelectricelement into motion of the cutting tip.
 22. The cutting instrument ofclaim 21, wherein the motion of the cutting tip has a larger amplitudethan the motion of the piezoelectric element.
 23. The cutting instrumentof claim 16, wherein the body further includes: a fluid input portarranged and configured to be coupled to a fluid source; a fluid outputport arranged and configured to deliver fluid proximate the cutting tip;and a fluid channel fluidly coupling the fluid input port to the fluidoutput port for supplying fluid from the fluid source through the fluidinput port to the fluid output port.
 24. A method, comprising:operating, via a user interface, an actuation mechanism with apiezoelectric element comprised in a body to cause motion in a cuttingtip; and extending the cutting tip, wherein the cutting tip isconfigured to match a curvature of an acetabular cup.
 25. The method ofclaim 24, further comprising causing fluid to exit a fluid output portproximate the cutting tip based on operation of the user interface. 26.The method of claim 24, further comprising operating the user interfaceto extend the cutting tip.
 27. The method of claim 24, wherein extensionof the cutting tip is configured to follow the curvature of theacetabular cup.
 28. The method of claim 24, further comprisingcontrolling one or more of amplitude and frequency of motion in thecutting tip based on operation of the user interface.